The following came across my desk via a listserv at the University of Minnesota:
My dear friend Rebecca is heartbroken over the quandary she now has with her two cats. They are of different ages and the younger has been behaving very badly, probably because it feels threatened the older (or so says the behaviorist). I know and adore Mabel (picture enclosed--not the blonde) and would take her in a minute if my current cat weren't so pissy about sharing space with other quadrapeds. Mabel is very laid back and low-maintenance...she's got a playful side but is NOT kittenesque in any way. If you're thinking about a cat, Mabel would make a fabulous pick. Let me know if you want more details, and please forward this to anyone you know who may be interested.
I've always thought that people today prefer pets to children because they aren't as demanding, I guess I never thought about the sibling rivalary issues!